I spent a few days lurking in the China channel. I went into it hating China, and came out cautiously optimistic, so I'll give this a go.

The rapid expansion of capital, foreign and local, and the reemergence of capital accumulation as a production goal in the end of the 20th century

So the basic reason for this is that the CCP wants to catch up to and surpass the US, as well as build the productive forces necessary for communism. Marx acknowledged that capitalism is very good at industrialisation, which is why the CCP is attempting to harness it. In general the goal of this is to use capital to build productive forces without becoming a bourgeois dictatorship, i.e. being under the domination of capital. So how's it been going?

Pretty well, to be honest. First, the ideology of the CCP. According to US National Security Advisor Robert C. O’Brien(1)

"As China grew richer and stronger, we believed, the Chinese Communist Party would liberalize to meet the rising democratic aspirations of its people...We could not have been more wrong-and this miscalculation is the greatest failure of American foreign policy since the 1930s. How did we make such a mistake?...The answer is simple: because we did not pay heed to the CCP’s ideology. Instead of listening to what CCP leaders were saying and reading what they wrote in their key documents, we closed our ears and our eyes. We believed what we wanted to believe-that the Party members were communist in name only. Let us be clear, the Chinese Communist Party is a Marxist-Leninist organization. The Party General Secretary Xi Jinping sees himself as Josef Stalin’s successor. In fact, as the journalist and former Australian government official John Garnaut has noted, the Chinese Communist Party is the last “ruling communist party that never split with Stalin, with the partial exception of North Korea."

Now O'Brien is obviously far from a trustworthy source. He may be attempting to stir up anti-China sentiment here. But you can at least be assured that this isn't CCP propaganda. The point of this program is that it allowed China to trade with the rest of the world. When SWCC was started, China was pretty weak. Look what happened to the USSR, even with how strong it is. Look what's happening to Cuba, Venezuela, Bolivia and the DPRK. Embargos, sanctions, and so on. By tricking the west into believing China would liberalise, it seems that China has managed to avoid being attacked by the west during a fairly critical period. This also allowed them to basically capture most of the west's heavy industry. Now the west has to keep trading with China, because it's entire economy is tied up in Chinese manufacturing.

Regarding Xi Jinping personally, the NY Times(Bad source, but not tankie propaganda) writes that "China watchers all need to stop saying this is all for show or that he’s turning left to turn right...[moving towards the left] is a core part of the guy’s personality. The leftists certainly feel he’s their guy."(6) This, combined with Xi's anti-corruption campaign, tells me that there was likely some sort of power struggle in the CCP, and the left won.

There's also the typical capitalist argument of poverty reduction, which may be relevant. China has gone from (the world bank's terrible definition) 66.2% poverty in 1990, to 0.5% in 2016,(2) but I'm not going to dwell on it, beyond noting that generally lower poverty rates are a sign of more developed capitalist economies, which is a prerequisite of communism.

The existence of megacorporations, especially private megacorporations such as tencent and foxconn

The main thing to note here is that the CCP doesn't appear to be controlled by billionaires, and thus is not under the thrall of capital. Chinese billionaires are often executed for breaking laws, for example.(3) Furthermore, examining their response to covid, China was able to shut down entire cities to fight it.(4) The west has been unable to do this, because that would dramatically impede the flow of capital. As stated above, the goal of the CCP in SWCC is to use capital to develop. So far, it appears that the CCP has mostly succeeded in keeping it's capitalists under control. Where the west is under the thrall of capital, the CCP seems able to tell capital to shove it when it wants.

the state of labor rights in the aforementioned megacorporations, and the state of labor rights in the industrial sector as a whole

This is a problem. Labour rights are bad in China, especially for migrant workers. There are attempts to address it,(5) which are unfortunately often opposed by the state. I remember seeing some sources in the China channel talking more about how the CCP does support labour action a lot, but since the channel is closed I can't find the sources. So please do note that while I'm negative here, there are positive aspects to worker's rights in China. I'm just trying to have sources for claims I'm making.

The repression of marxist and leftist protest and critique of the current state of the system

Since he came to power, Xi has emboldened maoists in China.(6) And there is critique and debate in the Chinese left.(7) A lot of it doesn't get seen over here, because it's in Chinese. I would also wager that, because of democratic centralism, we don't see most of the debate. This is an old source, but it's an account of a westerner going to a Chinese conference about policy.(8) So there is definitely western debate.

The apparent lack of repression of non-leftist critique (I could easily be convinced that this is just because they’re amplified by American media)

Probably this.

The great firewall (I could be convinced this is protectionism to avoid Western silicon valley capitalism’s supremacy on the internet)

There's an interview with Castro where he talks a bit about free speech in Cuba, and how it doesn't apply to people supporting Yankees. I think it's applicable here. Also, it seems pretty easy to get around the firewall, and no one seems to care.(9)

The social credit system

I don't know enough about it, but I've heard that it doesn't actually exist.

Uyghurs

Continued in reply

(1) https://www.miragenews.com/chinese-communist-party-s-ideology-and-global-ambitions/

(2) https://data.worldbank.org/indicator/SI.POV.DDAY?locations=CN

(3) https://www.huffingtonpost.ca/2014/05/26/billionaire-death-sentence-execution_n_5393883.html

(4) https://www.bloomberg.com/news/articles/2020-05-18/over-100-million-in-china-s-northeast-thrown-back-under-lockdown

(5) https://madeinchinajournal.com/2020/06/25/leninists-in-a-chinese-factory/

(6) https://www.nytimes.com/2015/01/05/world/chinas-maoists-are-revived-as-thought-police.html

(7) http://ouleft.sp-mesolite.tilted.net/?p=1621

(8) https://monthlyreview.org/2007/09/01/the-state-of-official-marxism-in-china-today/

(9) https://old.reddit.com/r/Kaiserreich/comments/hutfa5/explaining_the_chinese_kr_community_yes_we_do/